CN110610466B

CN110610466B - System and method for selectively enhancing a region of interest in an image

Info

Publication number: CN110610466B
Application number: CN201910797839.5A
Authority: CN
Inventors: 格伦·W·马克劳林; 路德温·斯蒂芬金
Original assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Current assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Priority date: 2014-05-30
Filing date: 2015-05-29
Publication date: 2023-05-09
Anticipated expiration: 2035-05-29
Also published as: CN110610466A; CN110533613A; CN110533613B; CN106659468B; US9911182B2; CN106659468A; US9460499B2; WO2015184300A1; US20180197280A1; US20150348247A1; US20170091915A1; US10223776B2

Abstract

The present application relates to systems and methods for receiving ultrasound image data corresponding to an ultrasound image having an active dynamic range and displaying a global tone map of the ultrasound image on an electronic display. A region of interest (ROI) within an ultrasound image may be region-tone mapped to provide an enhanced, optimized, and/or other improved ROI image. The regional tone mapping may allow features within the same ROI to be more easily discernable than features within the ROI that are not or not readily discernable by the global tone mapping.

Description

System and method for selectively enhancing a region of interest in an image

The application is a divisional application of the following parent application:

the parent application date is 2015.5.29, the national stage Chinese application number is 201580039885.9 (International application number is PCT/US 2015/033246), and the name is a system and method for selectively enhancing a region of interest in an image.

Technical Field

The present application relates to a system and method for viewing and enhancing ultrasound images, and more particularly to a system and method for enhancing a region of interest in ultrasound.

Disclosure of Invention

In various embodiments, the received ultrasound image may have a relatively high dynamic range. The electronic display may have a low dynamic range. Thus, it may be useful to generate a mapping of the available gray levels of the primary ultrasound image to the number of gray levels that can be displayed on the electronic display. The tone mapping or encoding of such gray levels may be performed linearly or non-linearly.

In various embodiments, the loss of grayscale resolution may make it difficult for a user to distinguish between various features of an ultrasound image. Various embodiments of the systems and methods described herein allow a user to select a portion of a main ultrasound image, i.e., a region of interest (ROI), for region tone mapping. The ROI may be displayed as an overlay image placed on the image after the global tone mapping, or as a replacement image for the image after the global tone mapping, or as a separate image. In some embodiments, the overlay image may be slightly expanded (magnified) and/or highlighted (e.g., bolded around the area, etc.).

In various embodiments, the region tone mapping of the ROI may include mapping the ROI tone of the main ultrasound image to a greater number of gray levels than is used in the global tone mapping of the same region.

In some embodiments, the regional tone mapping of the ROI may be different from the global tone mapping of the same region by using different linear mapping functions, gamma compression algorithms, gradient domain high dynamic range compression algorithms, gamma algorithms, logarithmic algorithms, histogram equalization algorithms, regional tone mapping algorithms, image decomposition, image gradients, inverse tone mapping algorithms, inverse linearization algorithms, and/or image tone model (iCAM), etc.

Accordingly, the systems and methods described herein may include: receiving, via the processor, ultrasound image data corresponding to an ultrasound image having an active dynamic range; generating a global tone mapping of the ultrasound image data to a displayable dynamic range, the displayable dynamic range being less than an active dynamic range of the ultrasound image; receiving information via an electronic input device to determine a selected region of the ultrasound image for regional tone mapping; and generating a portion of the ultrasound image data corresponding to the selected region to a region tone map that can display a dynamic range, wherein the region tone map of the selected region of the ultrasound image is different from the global tone map of the selected region of the ultrasound image.

The foregoing is illustrative of the present invention and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, other aspects, other embodiments, and features will become apparent by reference to the drawings and the following detailed description.

Drawings

FIG. 1 is a block diagram of a computer system for displaying enhanced or regional tone mapping of a selected region of interest (ROI).

FIG. 2 illustrates one embodiment of a method for generating a ROI with a regional tone map.

FIG. 3 is a set of graphical representations of various possible states and/or methods for remapping gray or luminance values from a primary image to generate a region tone map of a selected ROI.

FIG. 4 illustrates one embodiment of an enhanced ROI overlaid on a displayed ultrasound image.

Fig. 5 shows an embodiment of an enhanced ROI optionally overlaid on a displayed ultrasound image or displayed in a second separate window.

Fig. 6A and 6C show a screen shot of a user display screen displaying an ultrasound image including a substance located in the liver and representative diagrams of the screen shot, respectively.

Fig. 6B and 6D show a screen shot and representative diagrams of the screen shot, respectively, with a user display screen displaying an enhanced ROI on an ultrasound image of the liver.

Fig. 7A and 7C show a screen shot and a representative view of the screen shot, respectively, with a user display screen displaying an ultrasound image of the testis.

Fig. 7B and 7D show representative diagrams of a screen shot and a screen shot, respectively, with a user display screen showing an enhanced ROI on an ultrasound image of the testis.

Fig. 8 illustrates a typical global mapping of a main ultrasound image with a wide dynamic range to a displayable dynamic range of an electronic display.

Fig. 9 shows an embodiment of ROI area mapping in which gray or luminance values above a threshold are all mapped to a single gray value.

Fig. 10 illustrates an embodiment of ROI area mapping in which gray or luminance values above a threshold and below another threshold are combined.

Fig. 11 illustrates an embodiment of ROI area mapping in which gray or luminance values below a threshold are all mapped to a single gray value.

FIG. 12 illustrates one embodiment of a ROI nonlinear region map with greater resolution for darker shades.

FIG. 13 illustrates one embodiment of a ROI nonlinear region map with greater resolution for brighter shadows.

Detailed Description

The present application includes various embodiments of systems and methods for enhancing a region of interest (ROI) of an ultrasound image. It should be appreciated that the various embodiments of the present application may be applicable to other image types, image systems, and/or image display systems or methods. For example, the embodiments described herein may be applicable to x-ray images, computed Tomography (CT) images, and other modality medical images. Furthermore, various embodiments used herein relate to gray scale images and gray scale mapping. It should be appreciated that many of these embodiments may be replaced with color images and color tone maps.

Ultrasound imaging is a technique that can generate real-time high resolution and high dynamic range images of soft tissue structures. Unfortunately, in order to accurately represent the images, many local compromises have to be made, which potentially reduces the diagnostic information contained within each image.

In various embodiments, a system (e.g., a processor of the system) may receive ultrasound image data having a relatively high dynamic range. For example, the system may receive ultrasound images having a dynamic range of about 84-108 decibels (84-100 dB), which corresponds to gray levels between about 16,000 and 262,000 levels. Such images may be acquired using a digital imaging device of 14-18 bits per pixel. It should be understood that the embodiments described herein may also be applicable to higher (or lower) dynamic ranges, whether measured or expressed in dB, gray scale, or bits per pixel.

While the dynamic range of ultrasound image data may be relatively high, a typical 8-bit electronic display may only be able to accurately represent 256 gray levels (about 48 dB). Furthermore, under ideal lighting conditions, the human visual system may be able to discern a change of about 1024 gray levels (60 dB), but under ordinary lighting conditions this number may be reduced to only 64 gray levels (about 32 dB).

Thus, it may be useful to generate a mapping of 260,000+ gray levels of the main ultrasound image to a number of gray levels displayable on an electronic display (between 256 and 1024, or between an 8-bit display and a 10-bit display). In most cases, the dynamic range of the electronic display is smaller than the dynamic range of the main ultrasound image.

As described above, the active state range of the ultrasound image may exceed the displayable range of the electronic display. Thus, the active dynamic range spectrum (e.g., a spectrum of gray levels from 0 to 262,143 for an 18-bit image) may be globally tone mapped to a displayable dynamic range. Such global tone maps may be more or less compressed depending on the dynamic range of the main ultrasound image and the displayable dynamic range of the electronic display. Furthermore, tone mapping or encoding of gray levels may be performed linearly or non-linearly.

For example, a 16-bit ultrasound image (65,536 gray levels) may be globally tone mapped to an 8-bit display by linearly mapping 256 unique gray levels of the main ultrasound image to each displayable gray level of the 8-bit display. Dynamic range compression of the main ultrasound image may result in a significant loss of detail. For example, during global tone mapping of the primary ultrasound image to the displayable dynamic range, objects in the primary ultrasound image that are similar (but distinguishable differently) in gray shades may be mapped to the same (or indistinguishable differently) gray shades. Such global mapping of the entire image may lead to a number of unacceptable artifacts.

The image may also be tone mapped non-linearly. For example, a relatively darker primary ultrasound image may be globally tone mapped with a greater number of displayable gray levels for darker portions of the active dynamic range. Similarly, a relatively brighter main ultrasound image may be globally tone mapped with a greater number of displayable gray levels for the brighter portions of the active state range.

Whether the primary image is mapped linearly or non-linearly, the loss of grayscale resolution may make it difficult for a user (a human observer, a computer observer, or a combination thereof) to distinguish between the various features of the ultrasound image (or other image types as provided herein). Various embodiments of the systems and methods described herein allow a user to select a portion of a main ultrasound image, referred to herein as a ROI, for region tone mapping.

The regional tone mapping systems and methods described herein may be used for ROIs as overlay images placed over images that have been globally tone mapped, or displayed in separate windows. In some embodiments, the overlay image may be slightly enlarged (magnified) and/or highlighted (e.g., bolded border around the area, etc.).

In various embodiments, for the display of an entire ultrasound image, the regional tone mapping of the ROI may be different from the global tone mapping of the same ROI. The region tone mapping of the ROI may include tone mapping the ROI of the main ultrasound image to a greater number of gray levels than the number of gray levels used in the global tone mapping of the same region.

In some embodiments, the region tone map of the ROI may differ from the global tone map of the same region in any of a number of ways, including using different: linear mapping functions, gamma compression algorithms, gradient domain high dynamic range compression algorithms, gamma algorithms, logarithmic algorithms, histogram equalization algorithms, regional tone mapping algorithms, image decomposition, image gradients, inverse tone mapping algorithms, inverse linearization algorithms, and/or image color appearance models (icams), etc.

In various embodiments, the region tone mapping of the ROI may ignore brightness values of the ultrasound image data that exceed or fall below a threshold. The threshold may be determined based on the dynamic range of the primary ultrasound image and/or the displayable dynamic range of the electronic display.

Thus, the electronic system may be used to display the ultrasound image of the global tone map. The system may include one or more input devices to allow a user to make ROI selections in the displayed ultrasound image. The electronics can then generate a ROI region tone map for the same ROI that is different from the global tone map, and can display the region tone mapped ROI as an overlay image instead of the originally displayed image, or as a separate second image.

The regional tone mapping may provide a higher dynamic range for the tone mapping of the ROI than that used for the global tone mapping of the same region. The region tone map may also or alternatively include various other image adjustments as discussed herein, including image adjustments to the entire ROI or adjustments to selected ROI portions. Such image adjustments include, but are not limited to, adjusting contrast, brightness, sharpness, sharpening, blurring, and/or other useful image adjustments.

In various embodiments, the region tone mapping based on the dynamic range of the ROI may include generating a histogram of pixel intensities within the ROI, and generating a function to take the raw pixel intensity values and map them to modified pixel intensity values based on the histogram attributes of the ROI. The function may simply be a linear mapping of the minimum pixel to the minimum intensity, a linear mapping of the brightest pixel value to the maximum intensity, and a linear mapping of each pixel in between to a value that is the ratio of the pixel value minus the minimum value divided by the difference between the maximum and minimum values.

Alternative embodiments may include variations of the above examples in which the system may "threshold out" some of the lowest level values and/or some of the maximum level values. In some embodiments, statistically outliers may be excluded from the region map. In some embodiments, the system may consider the overall noise of the image. For example, pixel values at or below a certain gray level may be automatically or manually marked as system level noise and thus may be excluded from the region map.

Similarly, particularly bright areas may be caused by strong reflectors (e.g., boundaries between blood and tissue, mineral precipitation, etc.). Such bright areas may all be considered to be above a threshold and thus mapped to a maximum gray value for a particular region map. It should be appreciated that any number of image processing or image mapping methods and means may be utilized to generate the reduced dynamic range of the ROI, including the use of various gamma curves, inverse linearization functions, and the like.

Embodiments may include various steps that may be embodied in machine-executable instructions executed by a computer system. A computer system includes one or more general-purpose or special-purpose computers (or other electronic devices). The computer system may include hardware components for performing the specific logic of the steps, or may include a combination of hardware, software, and/or firmware.

Embodiments may also be provided as a computer program product containing a computer-readable medium having stored therein instructions, which may be used to program a computer system or other electronic device to perform the processes described herein. The computer readable medium may include, but is not limited to: hard disk drives, floppy disks, optical disks, CD-ROMs, DVD-ROM, ROM, RAM, EPROM, EEPROM, magnetic or optical cards, solid state memory devices, or other type of media/computer-readable media suitable for storing electronic instructions.

The computer system and the computers in the computer system may be connected via a network. Suitable network configurations and/or networks suitable for use described herein include one or more local area networks, wide area networks, metropolitan area networks, and/or the Internet or IP networks, such as the world Wide Web, an intranet, the private Internet, the secure Internet, a value-added network, a virtual private network, an extranet, or even a stand-alone machine that communicates with other machines through physical transmission of media. In particular, some or all of two or more other networks, including networks using different hardware and network communication technologies, may form a suitable network.

One suitable network includes a server and a number of clients; other suitable networks may include other combinations of servers, clients, and/or peer nodes, and a given computer system may act as both a client and a server. Each network includes at least two computers or computer systems, such as servers and/or clients. The computer system may include a workstation, a laptop computer, a removable mobile computer, a server, a mainframe, a cluster, a so-called "network computer" or "thin client," a tablet, a smart phone, a personal digital assistant, or other handheld computing device, "smart" consumer electronic device or apparatus, a medical device, or a combination thereof.

The network may include communications or networking software, such as that available from Novell, microsoft, artisoft and other suppliers, and may operate using TCP/IP, SPX, IPX and other protocols via twisted pair, coaxial or fiber optic cable, telephone lines, radio waves, satellites, microwave relays, modulated ac power lines, physical medium transmissions, and/or other data transmission "wires" known to those skilled in the art. The network may include smaller networks and/or may be connected to other networks through a gateway or similar mechanism.

Each computer system includes at least a processor and a memory; the computer system may also include various input devices and/or output devices. The processor may include general purpose devices such as

Or other "off-the-shelf microprocessor". The processor may include a special purpose processing device such as ASIC, soC, siP, FPGA, PAL, PLA, FPLA, PLD or other custom or programmable device. The memory may include static RAM, dynamic RAM, flash memory, one or more flip-flops, ROM, CD-ROM, magnetic disk, magnetic tape, optical disk or other computer storage medium. The input device may include a keyboard, mouse, touch screen, light pen, tablet, microphone, sensor, or other hardware with accompanying firmware and/or software. The output devices may include a monitor or other display, a printer, a voice or text synthesizer, a switch, a signal line, or other hardware with accompanying firmware and/or software.

The computer system may be capable of reading the storage medium using a floppy disk drive, a magnetic tape drive, an optical drive, a magneto-optical drive, or other means. Suitable storage media include magnetic, optical, or other computer-readable storage devices having a particular physical configuration. Suitable storage devices include floppy disks, hard disks, tape, CD-ROM, DVD, PROM, RAM, flash memory, and other computer system storage devices. Physical configuration represents data and instructions that cause a computer system to operate in a specific and predefined manner as described herein.

Appropriate software for assisting in the implementation of the present invention may be readily provided by those skilled in the relevant art using the teachings presented herein and employing programming languages and tools such as Java, pascal, C ++, C, database languages, APIs, SDKs, components, firmware, microcode, and/or other languages and tools. Suitable signal formats may be expressed in analog or digital form, with or without error detection and/or correction bits, packet headers, network addresses, and/or other support data readily provided by one of ordinary skill in the relevant art in a particular format.

Aspects of the described embodiments will be illustrated by software modules or components. As used herein, a software module or component may include any type of computer instructions or computer-executable code located within a memory device. A software module may, for example, comprise one or more physical or logical blocks of computer instructions, which may be organized as a routine, procedure, object, component, data structure, etc., that performs one or more tasks or implements particular abstract data types.

In certain embodiments, a particular software module may include different instructions stored in different locations of a memory device, different memory devices, or different computers, which together implement the described functional modules. Indeed, a module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across several memory devices. Some embodiments may be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, software modules may be located in local and/or remote memory storage devices. In addition, the data that is bound or presented together in a database record may reside in the same memory device or across several memory devices and may be linked with fields of records in the database across a network.

Many of the infrastructure that can be used in accordance with the invention are provided, for example, with general purpose computers, computer programming tools and techniques, computer networks and networking techniques, digital storage media, authentication, access control, and other security tools and techniques provided by public keys, encryption, firewalls, and/or other means.

Embodiments of the present application are described below with reference to the drawings, wherein like parts are designated by like numerals throughout. The components of the disclosed embodiments can be arranged and designed in a wide variety of different configurations as generally described and illustrated in the figures herein. Furthermore, the features, structures, and operations associated with one embodiment may be suitable for use in or in connection with the features, structures, or operations described in connection with another embodiment. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the application.

Thus, the following detailed description of the systems and methods of the present application is merely representative of possible embodiments and is not intended to limit the scope of the application as claimed. In addition, the steps of a method do not necessarily have to be performed in any particular order or even sequentially, nor are they limited to being performed only once.

FIG. 1 is a block diagram of a computer system 100 for displaying enhanced or regional tone mapping of a selected region of interest (ROI). As shown, the processor 130 may be in communication with a memory 140, a network interface 150, and/or a computer-readable medium 170 (e.g., a non-transitory computer-readable storage medium) via the bus 120. The computer-readable storage medium may include one or more modules implemented in hardware, firmware, and/or software for generating an enhanced tone mapping for the ROI. In various embodiments, one or more of the described modules may be removed and/or implemented by different systems at a later time or simultaneously. In some embodiments, some method steps and/or modules may be omitted.

In various embodiments, the receiver module 180 may be used to receive ultrasound image data corresponding to one or more ultrasound images. The received ultrasound image may have an active dynamic range that exceeds the displayable dynamic range of the associated electronic display. The global tone mapping module 182 may be used to generate a global tone mapping of ultrasound image data to a displayable dynamic range that is less than the active dynamic range and suitable for display on an associated electronic display. The display module 189 may facilitate displaying a global tone scale map of the ultrasound image.

The user input module 184 may be used to receive a selection of an ROI on the displayed globally tone mapped ultrasound image. The ROI may be determined, for example, by a user through the use of a cursor, mouse, keyboard, touch screen, or other input device. In various embodiments, the user adjustment module 186 may allow a user to specify one or more image enhancements, modifications, adjustments, processing means, and/or other changes to be performed on the ROI. The region tone mapping module 188 may be used to generate a region tone map of a portion of the ultrasound image data corresponding to the selected ROI. The region tone map may tone map the selected ROI for display on an electronic display, the region tone map using a different tone map than the global tone map used in the same region.

As previously described, one or more of the modules described herein may be omitted and/or combined with one or more other modules and/or implemented separately.

FIG. 2 illustrates one embodiment of a method 200 for generating a ROI with a regional tone map. The method 200 may begin when a user selects an ROI to be remapped (e.g., by region/enhancement tone mapping). In the illustrated embodiment for generating a region tone map, an ROI is received at step 201. At step 202, the system may determine a histogram of the ROI. The histogram may be derived based on pixel values (e.g., gray value/luminance value) and the number of pixels of the same value.

The histogram results may be sent to a mapping function module, step 203, which takes the information contained in the histogram and then creates a mapping of the original pixel values to modified/enhanced pixel values (optionally based on user-selected preferences). In step 204, the mapping function so generated may be remapped to the pixel intensities (luminance values) of the region.

In various embodiments, the remapped pixels may have a high level of discontinuity within the imaging region. Thus, one or more smoothing or transition algorithms may be applied to the ROI. For example, in step 205, a transition mask of the ROI may be generated, which provides a mask that may be used for smooth transitions. The transition mask may use, for example, a low pass filter and/or an adaptive direction-based filtering algorithm.

In step 206, a transition mask may be applied to the remapped image region luminance values in a weighted manner by a transition mask module. The module may be implemented based on user selectable parameters. For example, the user may select the percentage of the weight that should be applied to remap the ROI. The remapped ROI is then output for display on the electronic display as an independent image and/or as an overlay image on the original image, step 207.

FIG. 3 is a set of graphical representations 300 of various possible states and/or methods for remapping gray or luminance values from a primary image to generate a region tone map of a selected ROI. It should be appreciated that any one or more image mapping algorithms and methods may be used. For example, one approach that is not described is the inverse function of the cumulative distribution to generate a linear map of pixel density across the intensity region. Any suitable mapping function may be applied to the input data set to produce the desired result, or based on a defined set of characteristics.

The overall behavior of the automatic dynamic range optimization (i.e., region/enhancement tone mapping) may vary based on user preferences and imaging conditions. To maintain some continuity between images during a real-time scanning scenario, the auto-optimization parameters and/or the functional mapping (i.e., tone scale mapping) may be slowly changed based on user preferences. This will result in one type of functional map persistence. During frozen image and ROI movement, the functional map may be adjusted immediately to the selected ROI. In other embodiments, the function map may transition slowly.

Assuming that there are different preferences and comments for the user as to how to optimize the overall diagnostic information contained within each imaging condition (including heart, liver, kidney, breast, testis, etc.), and assuming that the user preferences, the system may provide various optimized objective mapping functions for the user to choose. For example, a presentation morphology may be generated for each of a variety of clinical situations. In some embodiments, the user may be able to save default settings and/or customize the presentation morphology. Such settings may be applied to a global tone mapped image and/or a regional tone mapped ROI.

Graphs 301-314 relate to various possible embodiments and adjustments for region tone mapping. Various alternative methods, intermediate steps, and alternative mapping methods are possible. Graph 301 schematically depicts an original histogram of pixel values in an ROI. Graph 302 shows a straight-through mapping function between original pixel values (input) to pixel values (output). The illustrated pass-through function is an identity function and, therefore, assigns the same value to the output pixel as the input pixel. Graph 303 shows the result of passing the histogram shown in graph 301 through the mapping function shown in graph 302; the result is virtually unchanged from graph 301.

Graph 304 shows the cumulative transfer function of the histogram (i.e., the integral of the number of pixels in the histogram of graph 302 with respect to the pixel value). The cumulative map can then be used to determine the optimal method of remapping pixels so that additional clinically relevant information can be displayed.

For example, graph 305 shows a threshold function using an upper threshold level 306 and a lower threshold level 307 to remove extreme high and low points that may not be desirable to deviate from the optimized image. Although an upper threshold and a lower threshold are shown, it is contemplated that only the upper threshold or only the lower threshold may be used.

Pixels below the threshold are mapped to zero intensity (black) and pixels with values above the threshold are mapped to maximum intensity (white). Pixels whose values are between the thresholds initially (i.e., in a global map of the same region) have a reduced range of values, but their values will be mapped to cover the full range or at least a larger range of gray/brightness available in the displayable dynamic range. As will be described below, the mapping may be selected.

Graph 308 shows how the transfer function of pixel values (input) to pixel values (output) is calculated once the appropriate out-of-threshold information is removed (i.e., pixels outside the threshold map to black or white). This can be optimized in a number of ways. One way is a linear mapping 310. Here two non-linear (curve) maps are shown: mapping 309 and mapping 311; the slope of the map 309 is a maximum at the lowest pixel value and decreases (i.e., toward the lower convex surface) as the pixel value increases; the slope of the map 311 is at a minimum at the lowest pixel value and increases (i.e., toward the concave surface of the bottom) as the pixel value increases.

The thresholding has the effect of providing an increased range of possible output pixel values for a truncated range of input pixel values, and thus causes an overall increase in contrast. This may increase the overall resolution of the image. In some cases, it may be desirable to enhance certain areas within the image. For example, curve 309 may be used for low intensity echoes and curve 311 may be used to suppress high intensity echoes.

In various embodiments, it may be desirable to manipulate certain regions within the image, with

non-linear mappings

309 and 311 providing examples of how this may be done. Graph 312 shows the result of applying the threshold of graph 305 to the acquired input histogram 301 and then applying a nonlinear ("convex") conversion map 309 to the pixel values. The result is that the lower intensity pixel values expand along the pixel value axis, while the higher intensity pixel values compress along the pixel value axis. Thus, a larger range of pixel values is provided for a region of the image (e.g., a low intensity echo) of lower intensity pixel values, and detail may be enhanced due to the increased contrast.

Graph 313 shows the result of applying the threshold value of graph 305 to the acquired input histogram 301 and then linear conversion mapping 310 the pixel values. The mapping itself does not affect the histogram, but the thresholding does increase the overall contrast and maximizes the use of the displayable dynamic range of the electronic display for the selected ROI.

Graph 314 shows the result of applying the threshold of graph 305 to the acquired input histogram 301 and then performing a nonlinear ("concave") conversion mapping 311 on the pixel values. The result is that lower intensity pixel values compress along the pixel value axis, while higher intensity pixel values expand along the pixel value axis. Thus, a larger range of pixel values is provided for a region of the image (e.g., a high intensity echo) of higher intensity pixel values, and detail may be enhanced due to the increased contrast.

Fig. 4 illustrates an embodiment of a display image of an ultrasound image in a display 401. In this embodiment, user display 400 is in a dual image format with

images

401 and 402 on the left and right sides, respectively. The image 401 is not enhanced. The non-enhanced image 401 is displayed so that the clinician can continue to refer to the global dynamic range map of the image shown. In some embodiments, image 401 may be omitted.

Image 402 shows similar information as image 401 but includes an overlaid ROI 403.ROI 403 is a user-selected ROI in which an enhanced or regional tone mapped image of the selected region may be displayed. The size of the ROI may be adjusted as indicated by arrow 404; but also up and down as shown by arrow 405; or may be moved from side to side as indicated by arrow 406. Based on any changes made in the ROI 403, the base image to be optimized/enhanced may be updated automatically or manually via the region tone map to accurately represent the base information.

In various embodiments, the ROI may be enlarged relative to the image 402. The amount of amplification may be selectively controlled by a user.

Fig. 5 shows an embodiment of an enhanced ROI 503 optionally overlaid on a displayed ultrasound image or displayed in a second separate window 501. In this implementation, as previously described, user display 500 is in a dual image format, with images 502 and 501. In this implementation, image 501 is an enlarged version of user-selected ROI 503 in image 502. As described above, the ROI 503 may change in response to user control—its size may be adjusted as indicated by arrow 504; can move up and down as shown by arrow 505; but may also move from side to side as indicated by arrow 506.

ROI 503 may be considered a magnifying glass approach that moves over a selected portion of image 502, with the magnified version displayed to the right as image 501. The information in the ROI 501 is optimized by, for example, region tone mapping based on optimal conditions or user-selected mapping functions. ROI 503 may be optimized based on the same function as ROI 501, or may be displayed in an unoptimized manner or alternatively optimized manner. The depicted embodiment shows that the ROI 503 is limited to a sound grid (acoustic grid); however, it should be understood that the ROI may be displayed on a cartesian grid or another suitable grid. In this case, the ROI 501 may be displayed according to the same system/grid or different coordinate systems/grids.

Fig. 6A and 6C show a screen shot 600 of a user display displaying an ultrasound image 601 comprising a substance located in the liver and a representation 650 of the screen shot 600, respectively. Image 601 shows an unmodified image.

Fig. 6B and 6D show a screen shot 690 and a representative view 695 of the screen shot 690, respectively, with a user display screen showing an enhanced ROI 603 on the liver ultrasound image 602. The displayed ultrasound image 602 shows an image with an overlaid ROI 603. The image contained within the overlaid ROI 603 is region tone mapped to increase the user's ability to distinguish between different features. As shown, the global tone map image 601 has difficulty in seeing the discontinuities that can be seen in the region tone mapped ROI 603. The ROI 603 can be moved and its size is adjustable. The basic parameters used to perform the region tone mapping of the ROI 603 may be modified based on clinician or other user preferences.

Fig. 7A and 7C show a screen shot 700 and a representative view 750 of screen shot 700, respectively, of a user display screen displaying an ultrasonic image 701 of the testis. Image 701 shows an unmodified image.

Fig. 7B and 7D show a screen shot 790 of a user display screen with an enhanced ROI 703 on an ultrasound image 702 of the testis and a representation 795 of the screen shot 790, respectively. Image 702 shows ROI 703 overlaid on image 702. The image contained within the overlaid ROI 703 is region tone mapped so that the vessel can be more clearly delineated than the original global tone mapped image 701. The ROI 703 can be moved, resized, and/or enlarged. The base parameters for performing image optimization (e.g., regional tone mapping) may be selected by a clinician or other user via human control, preset, graph, and/or based on the type of tissue being detected.

Fig. 8-13 illustrate various tone maps, including the global tone map of fig. 8 and the various possible regional tone maps of fig. 9-13. It should be appreciated that the illustrated example is merely exemplary, and that an almost infinite number of possible tone maps may be utilized, and in the illustrated embodiment, various shading patterns are used to represent gray tones to increase reproducibility. Thus, the shadow patterns used may represent gray shades, color shades, chromaticity, shading, opacity, reflectance values, and/or other image characteristics.

In addition, fig. 8-13 provide an example in which the active dynamic range of the ultrasound image contains 21 gray values (represented by different fill patterns), while the displayable dynamic range of the electronic display contains only 11 gray values. It should be appreciated that the actual dynamic range of an ultrasound image may be hundreds of thousands and the displayable dynamic range of an electronic display may be hundreds or even thousands.

As previously described, although various references herein relate to ultrasound image analysis and tone mapping, it should be appreciated that any of the various embodiments described herein may be applied to other types of image analysis and processing, including many medical imaging types.

Fig. 8 illustrates a typical global mapping of a main ultrasound image with a wide dynamic range to a displayable dynamic range of an electronic display. As shown, the top row shows the active dynamic range of an ultrasound image with 21 gray values. The bottom row shows a global dynamic mapping of 21 main gray values for display on an electronic display with a dynamic range of 11 gray values. As shown, the global tone mapping may be a compression of approximately 2:1. In some embodiments, the lack of detail may be more pronounced. For example, a 16-bit image that is globally tone mapped for display on an 8-bit electronic display may have a compression ratio approaching 256:1.

Fig. 9 shows an embodiment of region mapping of ROIs in which gray or luminance values above a threshold are all mapped to a single gray value. Again, the top row shows the active state range of an ultrasound image with 21 gray values. The bottom row shows the regional tone mapping, which is used to provide more resolution in the brighter tone. Thus, many darker shades can be assigned a black (or another shade).

Fig. 10 illustrates an embodiment of ROI area mapping in which gray level or luminance values above a threshold and below another threshold are combined. Again, the top row shows the active state range of an ultrasound image with 21 gray values. The bottom row shows the regional tone mapping, which is used to provide more resolution in the halftone. Thus, many darker hues may be assigned black (or another dark hue) and many lighter hues may be assigned white (or another bright hue).

Fig. 11 illustrates an embodiment of ROI area mapping in which gray levels or luminance values below a threshold are all mapped to a single gray value. Again, the top row shows the active state range of an ultrasound image with 21 gray values. The bottom row shows the regional tone mapping, which is used to provide more resolution in darker hues. Thus, many brighter hues may be assigned a white (or another bright hue).

FIG. 12 illustrates one embodiment of nonlinear region mapping of a ROI with greater resolution for darker shades. Again, the top row shows the active state range of an ultrasound image with 21 gray values. The bottom row shows a non-linear area tone mapping from 21 gray values to 11 gray values, which has more resolution in brighter tones.

FIG. 13 illustrates one embodiment of nonlinear region mapping of a ROI with greater resolution for brighter shadows. Again, the top row shows the active dynamic range of an ultrasound image with 21 gray values. The bottom row shows a non-linear area tone mapping from 21 gray values to 11 gray values, which has more resolution in darker shades.

Again, there may be an almost infinite number of possible tone scale mappings, so only a few simplified examples are shown here. The present application has been accomplished with reference to various exemplary embodiments, including the best mode. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of the present application. While the principles of the present application have been described in various embodiments, numerous modifications of structure, arrangement, proportions, elements, materials, and components may be used in the practice of the invention, which are particularly adapted to specific environments and/or operative without departing from the principles and scope of the present application. These and other changes or modifications are intended to be included within the scope of the present application.

The present embodiments are to be considered as illustrative and not restrictive, and all such modifications are intended to fall within the scope of the present embodiments. Likewise, benefits, other advantages, and solutions to problems have been described above with regard to various embodiments. However, the benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or element. The scope of the application is, therefore, indicated by the appended claims.

Claims

1. A method for enhancing an ultrasound image region, the method comprising:

receiving, via the processor, ultrasound image data corresponding to an ultrasound image having an active dynamic range;

generating a global tone mapping of the primary ultrasound image to a displayable dynamic range, the displayable dynamic range being less than the active dynamic range of the ultrasound image;

receiving information via an electronic input device that determines a selected region of the ultrasound image for enhancing the tone scale map;

displaying an area tone map of the selected area of the ultrasound image on the electronic display;

wherein the region tone map is adjusted to the selected region immediately or transitions to the selected region slowly, the region tone map of the selected region of the ultrasound image increasing at least one of dynamic range, contrast, brightness, sharpness, sharpening, blurring of the entire selected region or of a portion of the selected region relative to the global tone map of the selected region of the ultrasound image.

2. The method of claim 1, wherein the ultrasound image comprises a grayscale image, wherein the global tone map comprises a global grayscale map, wherein the regional tone map comprises a regional grayscale map.

3. The method of claim 1, further comprising:

a global tone map of the ultrasound image within a displayable dynamic range is displayed on the electronic display.

4. The method of claim 3, wherein displaying the region tone map of the selected region of the ultrasound image comprises displaying the region tone map of the selected region of the ultrasound image as an overlay over a global tone map of the ultrasound image displayed.

5. The method of claim 4, wherein the overlay area tone map for the selected area is enlarged onto the electronic display relative to the global tone map for the displayed selected area.

6. The method of claim 1, wherein a dynamic range of the region tone map for the selected region of the ultrasound image is greater than a dynamic range of the selected region in the global tone map.

7. The method of claim 1, wherein the regional tone map and the global tone map both comprise linear tone maps of the ultrasound image data; wherein for a gray scale spectrum of ultrasound image data, the region tone map of the selected region is shifted relative to the global tone map of the same region.

8. The method of claim 1, wherein generating a regional tone map of the ultrasound image comprises one or more of the following functions: linear mapping functions, gamma compression algorithms, gradient domain high dynamic range compression algorithms, gamma algorithms, logarithmic algorithms, histogram equalization algorithms, regional tone mapping algorithms, image decomposition, image gradients, inverse tone mapping algorithms, inverse linearization algorithms, and/or image color appearance models (icams).

9. The method of claim 1, wherein generating the regional tone map for the ultrasound image includes ignoring intensity values for ultrasound image data below a minimum threshold and intensity values for ultrasound image data above a maximum threshold.

10. The method of claim 1, wherein receiving information for determining the selected region comprises receiving user input of an ultrasound image displayed on an electronic display.

11. The method of claim 1, wherein receiving information for determining the selected region comprises receiving information for determining a region that may be associated with a vascular structure.

12. The method of claim 1, wherein receiving information for determining the selected region comprises receiving information for determining a region that may be related to a boundary of two or more different organizations.

13. The method of claim 1, wherein generating the region tone map for the selected region comprises tone mapping based on one of a user selected preset and a user selected image adjustment.

14. A method for displaying an enhanced region of interest, the method comprising:

displaying a global tone map of the ultrasound image via the electronic display;

receiving a selection of a region of interest within the displayed ultrasound image via an electronic input device;

displaying a region tone map of a region of interest via the electronic display, wherein the region tone map is immediately tuned to the region of interest or slowly transitioned to the region of interest, the region tone map of the region of interest of the ultrasound image increasing at least one of dynamic range, brightness, sharpness, sharpening, blurring of the entire region of interest or portions of the region of interest relative to a global tone map of the region of interest of the ultrasound image.

15. The method of claim 14, wherein displaying the region-of-interest tone map comprises displaying the region-of-interest tone map as an overlay of a global tone map of the displayed ultrasound image.

16. The method of claim 14, further comprising:

receiving one or more tone mapping parameters from a user;

wherein the region tone mapping of the region of interest is performed based on the one or more tone mapping parameters.

17. The method of claim 14, further comprising:

receiving a tone mapping preset selected by a user from a plurality of available tone mapping presets;

wherein displaying the region-of-interest tone map comprises displaying the region of interest according to the selected tone map presets.

18. The method of claim 17, wherein the plurality of available tone mapping presets includes one or more mapping presets for viewing ultrasound images related to liver, kidney, breast, testis, vascular structures, and connections of two or more tissue types.

19. The method of claim 14, further comprising:

adjusting one of a size and a relative position of the region of interest; and displaying the refreshed region tone mapping of the region of interest based on the adjusted region of interest.

20. The method of claim 19, wherein displaying the refreshed region-tone map of the region of interest comprises gradually transitioning the displayed region of interest from an initial region-tone map to a refreshed region-tone map.

21. The method of claim 14, wherein displaying the region-tone map of the region of interest comprises magnifying the region-tone map of the region of interest relative to a global tone map of the same region of interest displayed.

22. The method of claim 14, wherein the received region of interest is defined as a raster associated with a global tone map of the displayed ultrasound image.

23. The method of claim 14, wherein the received region of interest corresponds to a region determined to be associated with one of a vascular structure and dissimilar tissue.

24. The method of claim 14, wherein a dynamic range of a region tone map for a region of interest is greater than a dynamic range of a region tone map for the same region of interest.

25. The method of claim 14, wherein the regional tone mapping comprises one or more of: linear mapping functions, gamma compression algorithms, gradient domain high dynamic range compression algorithms, gamma algorithms, logarithmic algorithms, histogram equalization algorithms, regional tone mapping algorithms, image decomposition, image gradients, inverse tone mapping algorithms, inverse linearization algorithms, and/or image color appearance models (icams).

26. The method of claim 14, wherein determining the regional tone mapping comprises:

setting a brightness value of the ultrasonic image data below a minimum threshold value to be equal to black;

the brightness value of the ultrasound image data above the maximum threshold is set to the value of white.